ultrasonic-app-subsonic-android/subsonic-api/src/main/kotlin/org/moire/ultrasonic/api/subsonic/SubsonicAPIClient.kt

package org.moire.ultrasonic.api.subsonic

import com.fasterxml.jackson.databind.DeserializationFeature
import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.module.kotlin.KotlinModule
import com.fasterxml.jackson.module.kotlin.readValue
import okhttp3.OkHttpClient
import okhttp3.ResponseBody
import okhttp3.logging.HttpLoggingInterceptor
import org.moire.ultrasonic.api.subsonic.interceptors.PasswordHexInterceptor
import org.moire.ultrasonic.api.subsonic.interceptors.PasswordMD5Interceptor
import org.moire.ultrasonic.api.subsonic.interceptors.RangeHeaderInterceptor
import org.moire.ultrasonic.api.subsonic.response.StreamResponse
import org.moire.ultrasonic.api.subsonic.response.SubsonicResponse
import retrofit2.Response
import retrofit2.Retrofit
import retrofit2.converter.jackson.JacksonConverterFactory
import java.util.concurrent.TimeUnit.MILLISECONDS

private const val READ_TIMEOUT = 60_000L

/**
 * Subsonic API client that provides api access.
 *
 * For supported API calls see [SubsonicAPIDefinition].
 *
 * @author Yahor Berdnikau
 */
class SubsonicAPIClient(baseUrl: String,
                        username: String,
                        private val password: String,
                        clientProtocolVersion: SubsonicAPIVersions,
                        clientID: String,
                        debug: Boolean = false) {
    private val okHttpClient = OkHttpClient.Builder()
            .readTimeout(READ_TIMEOUT, MILLISECONDS)
            .addInterceptor { chain ->
                // Adds default request params
                val originalRequest = chain.request()
                val newUrl = originalRequest.url().newBuilder()
                        .addQueryParameter("u", username)
                        .addQueryParameter("v", clientProtocolVersion.restApiVersion)
                        .addQueryParameter("c", clientID)
                        .addQueryParameter("f", "json")
                        .build()
                chain.proceed(originalRequest.newBuilder().url(newUrl).build())
            }
            .addInterceptor(RangeHeaderInterceptor())
            .apply { if (debug) addLogging() }
            .addPasswordQueryParam(clientProtocolVersion)
            .build()

    private val jacksonMapper = ObjectMapper()
            .configure(DeserializationFeature.UNWRAP_ROOT_VALUE, true)
            .configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false)
            .registerModule(KotlinModule())

    private val retrofit = Retrofit.Builder()
            .baseUrl("$baseUrl/rest/")
            .client(okHttpClient)
            .addConverterFactory(JacksonConverterFactory.create(jacksonMapper))
            .build()

    val api: SubsonicAPIDefinition = retrofit.create(SubsonicAPIDefinition::class.java)

    /**
     * Convenient method to get cover art from api using item [id] and optional maximum [size].
     *
     * It detects the response `Content-Type` and tries to parse subsonic error if there is one.
     *
     * Prefer this method over [SubsonicAPIDefinition.getCoverArt] as this handles error cases.
     */
    fun getCoverArt(id: String, size: Long? = null): StreamResponse = handleStreamResponse {
        api.getCoverArt(id, size).execute()
    }

    /**
     * Convenient method to get media stream from api using item [id] and optional [maxBitrate].
     *
     * Optionally also you can provide [offset] that stream should start from.
     *
     * It detects the response `Content-Type` and tries to parse subsonic error if there is one.
     *
     * Prefer this method over [SubsonicAPIDefinition.stream] as this handles error cases.
     */
    fun stream(id: String, maxBitrate: Int? = null, offset: Long? = null): StreamResponse =
            handleStreamResponse {
                api.stream(id, maxBitrate, offset = offset).execute()
            }

    /**
     * Convenient method to get user avatar using [username].
     *
     * It detects the response `Content-Type` and tries to parse subsonic error if there is one.
     *
     * Prefer this method over [SubsonicAPIDefinition.getAvatar] as this handles error cases.
     */
    fun getAvatar(username: String): StreamResponse = handleStreamResponse {
        api.getAvatar(username).execute()
    }

    private inline fun handleStreamResponse(apiCall: () -> Response<ResponseBody>): StreamResponse {
        val response = apiCall()
        return if (response.isSuccessful) {
            val responseBody = response.body()
            val contentType = responseBody.contentType()
            if (contentType != null &&
                    contentType.type().equals("application", true) &&
                    contentType.subtype().equals("json", true)) {
                val error = jacksonMapper.readValue<SubsonicResponse>(responseBody.byteStream())
                StreamResponse(apiError = error.error, responseHttpCode = response.code())
            } else {
                StreamResponse(stream = responseBody.byteStream(),
                        responseHttpCode = response.code())
            }
        } else {
            StreamResponse(responseHttpCode = response.code())
        }
    }

    /**
     * Get stream url.
     *
     * Calling this method do actual connection to the backend, though not downloading all content.
     *
     * Consider do not use this method, but [stream] call.
     */
    fun getStreamUrl(id: String): String {
        val request = api.stream(id).execute()
        val url = request.raw().request().url().toString()
        if (request.isSuccessful) {
            request.body().close()
        }
        return url
    }

    private fun OkHttpClient.Builder.addLogging() {
        val loggingInterceptor = HttpLoggingInterceptor()
        loggingInterceptor.level = HttpLoggingInterceptor.Level.BODY
        this.addInterceptor(loggingInterceptor)
    }

    private fun OkHttpClient.Builder.addPasswordQueryParam(
            clientProtocolVersion: SubsonicAPIVersions): OkHttpClient.Builder {
        if (clientProtocolVersion < SubsonicAPIVersions.V1_13_0) {
            this.addInterceptor(PasswordHexInterceptor(password))
        } else {
            this.addInterceptor(PasswordMD5Interceptor(password))
        }
        return this
    }
}